I tried trading there a few months ago (you can read my experiences in full
here). I had been trading doges before and right after the hack, and what I saw last time can't be called trading by any means. The order-books are literally frozen, and I don't think that with other coins it is substantially different (I looked at a few other coins as well). Some trading volume may be coming from the BTY-CNY section (if they are allowed to trade fiat at all), but I didn't check that. At any rate, they are nowhere near 300 BTC of daily trading volume
I didn't know that their trading volume can be manipulated
You can easily check it through a bot
Personally, I drew such a conclusion looking at the order-books which are scarcely moving, I'd been trading, or rather trying to trade there for a few hours (dogecoins specifically), and I saw only a few small trades. But they have a pretty decent and thought out api (in fact, the only exchange employing asynchronous api among those which I tested myself) which allows to track trades in real time (apart from many other things), so if you are really interested in finding this out, you could write a simple bot which would count the exact value of trading volume at Bter